Role of Troponins I and T and N-Terminal Prohormone of Brain Natriuretic Peptide in Monitoring Cardiac Safety of Patients With Early-Stage Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer Receiving Trastuzumab: A Herceptin Adjuvant Study Cardiac Marker Substudy

The breast cancer patient in the cardioncology unit

The breakthroughs of breast cancer management have led to a significant improvement in patient survival. However, to obtain this outcome a considerable price has been paid regarding cardiovascular side effects. Indeed, cardiovascular disease is the main cause of mortality in patients with breast cancer over fifty years of age, contributing more than cancer mortality in older cancer survivors. Thus, the identification and the management of patients with breast cancer at risk for cardiovascular events has become critical in order to reduce morbidity and mortality from cardiovascular toxicity due to cancer therapy, which may blunt its effectiveness. Today, cardioncology is a novel and recognized medical discipline, which aims to encourage a close interaction between cardiology and oncology, explore new strategies, collect evidence-based indications, and develop interdisciplinary expertise with the ultimate goal of minimize the risk of developing cardiovascular disease during and after anticancer therapy, prevent the breast cancer patient cured today from becoming the heart patient of tomorrow, and avoiding the possibility that pre-existent cardiac disease be a barrier leading to a reduction of a patient's therapeutic opportunities. In this review we discussed the advantages of a cardioncology approach in terms of risk stratification, monitoring for early diagnosis, prevention, and early treatment of cardiotoxicity.

Prolonged electromechanical delay as an early predictor of trastuzumab-induced cardiotoxicity in patients undergoing treatment for breast cancer

BACKGROUND

We aimed to investigate if left ventricular electromechanical delay (LVEMD) prolongation predicts trastuzumab-induced cardiotoxicity (TIC) in breast cancer patients.

HYPOTHESIS

LVEMD prolongation on serial echocardiograms could be an indicator of subclinical TIC.

METHODS

We included 237 breast cancer patients receiving trastuzumab chemotherapy, who underwent echocardiography at baseline and at 6 and 12 months after trastuzumab initiation. LVEMD was defined as the time from electrical activation to myocardial contraction. TIC was defined as left ventricular ejection fraction (LVEF) worsening to <55%, either as symptomatic decrease of ≥5% or asymptomatic decrease of ≥10%.

RESULTS

During a mean follow-up of 547 days, TIC occurred in 27 patients (11.4%). Changes in the time intervals from QRS onset on electrocardiography to the beginning and peak of transaortic flow on pulsed-wave Doppler echocardiography (ie, ΔLVEMDi and ΔLVEMDp, respectively) were independent predictors of TIC. On receiver operating characteristic curve analysis, the optimal cutoff value for TIC prediction was 23 milliseconds for ΔLVEMDi (sensitivity, 0.85; specificity, 0.78; area under the curve [AUC], 0.882) and 21 milliseconds for ΔLVEMDp (sensitivity, 0.96; specificity, 0.68; AUC, 0.860). The C-index for TIC prediction increased significantly after adding ΔLVEMDi and ΔLVEMDp to conventional models that included clinical variables, baseline LVEF, and changes in global longitudinal peak systolic strain. Similarly, adding ΔLVEMDi or ΔLVEMDp to conventional models provided significant improvement in discrimination capability for TIC prediction (integrated discrimination improvement and continuous net reclassification improvement index).

CONCLUSION

ΔLVEMDi and ΔLVEMDp may serve as predictors of subclinical cardiac dysfunction in breast cancer patients receiving trastuzumab.

Cardiovascular safety of oncologic agents: a double-edged sword even in the era of targeted therapies - Part 2

INTRODUCTION

Patients with cancer are subject to the cardiotoxic effects of cancer therapy. Improved cancer treatments lead to more cancer-survivors, who though are exposed to various forms of cardiovascular (CV) disease (CVD) as they age. Aging patients are at increased risk of developing both malignancy and CVD or they may have survived some form of CVD as a result of effective CV treatments. Furthermore, patients with CVD may develop cancer and require treatment (and vice versa), all contributing to increased morbidity and mortality. The prevalence of both malignancy and CVD will increase due to the trend toward a longer lifespan.

AREAS COVERED

In part 2 of this review, the discussion of the CV effects of specific oncology drugs is completed with inclusion of additional immunological agents, current hormonal and other agents. Early detection and monitoring of cardiotoxicity, use of biomarkers and other imaging and diagnostic methods and prevention and treatment options are also discussed.

EXPERT OPINION

As outlined in part 1 of this review, oncologists need to be aware of the CV adverse-effects of their treatments and make careful and expectant clinical decisions, especially in patients with preexisting CVD or CV risk factors. Similarly, cardiologists should consider a detailed previous history of treatment for malignant disease, including prior chemotherapy exposure, dose(s) received, and/or combined modality therapy with chest radiotherapy. Both specialists should collaborate in order to minimize the impact of these two ubiquitous diseases (cancer and CVD) and mitigate the adverse effects of treatment modalities.

Role of Biomarkers in Prediction of Cardiotoxicity During Cancer Treatment

Purpose of review

As cancer survivor rates improve with early screening and modern treatment options, cardiotoxicity is becoming an increasing problem. It is imperative for physicians to recognize adverse events early so that appropriate measures can be taken before advanced and permanent cardiac dysfunction ensues. In this review, we will evaluate the literature surrounding current cardiac biomarkers in the detection of cardiotoxicity during cancer treatment as well as discuss the role of emerging novel biomarkers.

Recent findings

Troponin and brain natriuretic peptides show promise in the detection of subclinical cardiotoxicity during cancer treatment. In addition to identifying late complications among cancer survivors, they have the potential to predict patients who are at risk of developing cardiotoxicity prior to the initiation of cancer therapy. However, there are also conflicting data due to varying study design.

Summary

Although biomarkers are an attractive option in the detection of cardiotoxicity among cancer patients, current recommendations surrounding its role are based on expert consensus opinion. Further research with appropriately designed prospective trials is required to guide optimal clinical practice.

Pharmacodynamic modeling of cardiac biomarkers in breast cancer patients treated with anthracycline and trastuzumab regimens

Trastuzumab is associated with cardiotoxicity, manifesting as a decrease of the left-ventricular ejection fraction (LVEF). Administration of anthracyclines prior to trastuzumab increases risk of cardiotoxicity. High-sensitive troponin T and N-terminal-pro-brain natriuretic peptide (NT-proBNP) are molecular markers that may allow earlier detection of drug-induced cardiotoxicity. In this analysis we aimed to quantify the kinetics and exposure–response relationships of LVEF, troponin T and NT-proBNP measurements, in patients receiving anthracycline and trastuzumab. Repeated measurements of LVEF, troponin T and NT-proBNP and dosing records of anthracyclines and trastuzumab were available from a previously published clinical trial. This trial included 206 evaluable patients with early breast cancer. Exposure to anthracycline and trastuzumab was simulated based on available dosing records and by using a kinetic-pharmacodynamic (K-PD) and a fixed pharmacokinetic (PK) model from literature, respectively. The change from baseline troponin T was described with a direct effect model, affected by simulated anthracycline concentrations, representing myocyte damage. The relationship between trastuzumab and LVEF was described by an indirect effect compartment model. The EC₅₀ for LVEF decline was significantly affected by the maximum troponin T concentration after anthracycline treatment, explaining 15.1% of inter-individual variability. In this cohort, NT-proBNP changes could not be demonstrated to be related to anthracycline or trastuzumab treatment. Pharmacodynamic models for troponin T and LVEF were successfully developed, identifying maximum troponin T concentration after anthracycline treatment as a significant determinant for trastuzumab-induced LVEF decline. These models can help identify patients at risk of drug-induced cardiotoxicity and optimize cardiac monitoring strategies.

Cardiac biomarkers for early detection and prediction of trastuzumab and/or lapatinib-induced cardiotoxicity in patients with HER2-positive early-stage breast cancer: a NeoALTTO sub-study (BIG 1-06)

BACKGROUND

Biomarkers of cardiac damages, such as troponin T (TnT) and the amino-terminal fragment of brain natriuretic peptide (NT-proBNP), may be useful as early predictors of cardiac dysfunction. The role of these biomarkers in patients receiving lapatinib and/or trastuzumab before anthracyclines is unknown. This study explores TnT and NT-proBNP as predictors of early cardiac toxicity in neoadjuvant breast cancer patients.

METHODS

This sub-study of the NEOALTTO trial tested if changes in the levels of TnT and NT-proBNP occurred after 2 weeks of anti-HER2 therapy (lapatinib, trastuzumab or their combination) alone and/or after 18 weeks of anti-HER2 therapy plus weekly paclitaxel.

RESULTS

173 and 172 were tested at all three timepoints for NT-proBNP and TnT, respectively. The incidence of biomarker elevation was overall low at all timepoints for all the three treatment arms. A total of 13 CEs in 11 patients occurred. Biomarker elevations in patients with CEs were very rare; only one patient with subsequent CE had a NT-proBNP elevation at baseline and at week 2.

CONCLUSION

These results suggest that TnT and proBNP may not be useful as early predictors of cardiac toxicity in anthracycline-naïve patients receiving trastuzumab and/or lapatinib.

Breast cancer treatment-induced cardiotoxicity

INTRODUCTION

Breast cancer is the most frequent cancer affecting women worldwide. In every setting, the majority of women are treated with an evergrowing arsenal of therapeutic agents that have greatly improved their outcomes. However, these therapies can also be associated with significant adverse events. Areas covered: This review aims to thoroughly describe the current state of the evidence regarding the potential cardiotoxicity of agents commonly used in the treatment of breast cancer. These include chemotherapeutic agents, anti-HER2 therapies and CDK4/6 and mTOR inhibitors. Furthermore, issues related to the risk stratification and monitoring tools are explored. Expert opinion: Anthracycline- and trastuzumab-related cardiac toxicities have been extensively studied. Substantial evidence is now available concerning additional anti-HER2 agents such as pertuzumab, T-DM1 and tyrosine kinase inhibitors; overall, the cardiotoxicity profile is reassuring. Cardiac events due to endocrine therapy are mostly ischemic and, in the context of prolonged therapy, need specific attention. Novel agents implicated in the treatment of hormone receptor-positive disease are potentially arrhythmogenic and the exact risk will need to be further refined. As for today, assessment of baseline risk factors prior to treatment initiation and cardiac imaging before and during treatment remains the optimal way to prevent cardiac dysfunction. Cardioprotective therapy in primary prevention is still a matter of debate.

Arginine-Nitric Oxide Metabolites and Cardiac Dysfunction in Patients With Breast Cancer

BACKGROUND

Oxidative/nitrosative stress and endothelial dysfunction are hypothesized to be central to cancer therapeutics-related cardiac dysfunction (CTRCD). However, the relationship between circulating arginine-nitric oxide (NO) metabolites and CTRCD remains unstudied.

OBJECTIVES

This study sought to examine the relationship between arginine-NO metabolites and CTRCD in a prospective cohort of 170 breast cancer patients treated with doxorubicin with or without trastuzumab.

METHODS

Plasma levels of arginine, citrulline, ornithine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and N-monomethylarginine (MMA) were quantified at baseline, 1 month, and 2 months after doxorubicin initiation. Determinants of baseline biomarker levels were identified using multivariable linear regression, and Cox regression defined the association between baseline levels and 1- or 2-month biomarker changes and CTRCD rate in 139 participants with quantitated echocardiograms at all time points.

RESULTS

Age, hypertension, body mass index, and African-American race were independently associated with ≥1 of baseline citrulline, ADMA, SDMA, and MMA levels. Decreases in arginine and citrulline and increases in ADMA were observed at 1 and 2 months (all p < 0.05). Overall, 32 participants experienced CTRCD over a maximum follow-up of 5.4 years. Hazard ratios for ADMA and MMA at 2 months were 3.33 (95% confidence interval [CI]: 1.12 to 9.96) and 2.70 (95% CI: 1.35 to 5.41), respectively, and 0.78 (95% CI: 0.64 to 0.97) for arginine at 1 month.

CONCLUSIONS

In breast cancer patients undergoing doxorubicin therapy, early alterations in arginine-NO metabolite levels occurred, and early biomarker changes were associated with a greater CTRCD rate. Our findings highlight the potential mechanistic and translational relevance of this pathway to CTRCD.

Developing a Comprehensive Cardio-Oncology Program at a Cancer Institute: The Moffitt Cancer Center Experience

Cardio-oncology is a multidisciplinary field focusing on the management and prevention of cardiovascular complications in cancer patients and survivors. While the initial focus of this specialty was on heart failure associated with anthracycline use, novel anticancer agents are increasingly utilized and are associated with many other cardiotoxicities including hypertension, arrhythmias and vascular disease. Since its inception, the field has developed at a rapid pace with the establishment of programs at many major academic institutions and community practices. Given the complexities of this patient population, it is important for providers to possess knowledge of not only cardiovascular disease but also cancer subtypes and their specific therapeutics. Developing a cardio-oncology program at a stand-alone cancer center can present unique opportunities and challenges when compared to those affiliated with other institutions including resource allocation, cardiovascular testing availability and provider education. In this review, we present our experiences establishing the cardio-oncology program at Moffitt Cancer Center and provide guidance to those individuals interested in developing a program at a similar independent cancer institution.

Cardiac safety, efficacy, and correlation of serial serum HER2-extracellular domain shed antigen measurement with the outcome of the combined trastuzumab plus CMF in women with HER2-positive metastatic breast cancer: results from the EORTC 10995 phase II study

PURPOSE

Cardiotoxicity is a side effect of trastuzumab. We assessed efficacy and cardiac safety of CMF with trastuzumab (CMF+T) in HER2-positive metastatic breast cancer patients (MBC).

METHODS

In this phase II study, centrally confirmed, previously treated HER2-positive MBC patients with measurable disease (per RECIST v 1.0) were enrolled. Initially, patients were randomized between 8 CMF cycles alone or combined with trastuzumab during chemotherapy, followed by 3-weekly trastuzumab maintenance till progression. A protocol amendment dropped the CMF arm and thereafter all patients received CMF+T. Translational research for prediction of treatment benefit was performed through serial serum HER2-shed antigen assessments.

RESULTS

Ninety patients (CMF: 19; CMF+T: 71) were enrolled between 2002 and 2006. Median age was 54 years. 42 patients had prior chemotherapy (33 with anthracyclines) and 41/71 patients who received CMF+T continued trastuzumab monotherapy for a median duration of 40 weeks. Overall response rate was 50% for CMF+T (35/70) and 32% for CMF (6/19). Median duration of response was 10.3 months and 5.4 months, respectively. Median progression-free survival was 9.4 months (95% CI 8.1-11.6) and 4.8 months (95% CI 2.8-7.9), respectively. In the CMF+T arm, 13(18%) patients had an absolute LVEF decline, including 3 patients developing any grade of New York Heart Association cardiac dysfunction. Patients with an increase of 30% over baseline shed antigen had a higher progression risk (95% CI 7.6, 3.9-14.8).

CONCLUSIONS

CMF+T is effective, with an acceptable cardiotoxicity profile. LVEF declines were mostly asymptomatic and occurred irrespective of previous anthracycline exposure. CMF+T can be considered for these patients, if other cytotoxics are contraindicated.